Written Paper

Linear growth stages in the rock lobster (Panulirus versicolor) as a method for determining size at first physical maturity [leg length, carapace length ratio, Australia]  [1979]

George, R.W. (Western Australian Museum, Perth) Morgan, G.R.

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Like several other species of rock lobster, Panulirus versicolor shows a marked increase in the leg length/carapace length ratio of the front legs of large males; large females show a decrease in this ratio for all five pairs of legs. Intersect analyses of two separate linear relations of leg length against carapace length below 6.0 cm (immature) and above 8.0 cm (mature) carapace length have provided estimates of the size at whcih immature specimens of each sex first begin to develop mature morphological features. Males of P. versicolor, on these analyses, mature at a larger size than females. The method should be equally applicable to other species which show measurable morphological changes after maturity and it is suggested that the "allometric" growth curves which have been presented for some other crustaceans may be better interpreted as two separate linear relationships.